Lighting units may be applied to backlight units used in flat panel displays, to indoor/outdoor billboards, to indoor lamps used in an indoor environment, to lamps installed in the exterior of a vehicle such as headlamps, fog lamps, retreat lights, sidelights, license plate lights, taillights, stop lamps, turn signal lamps, or hazard flasher lamps, or to indoor lights installed inside the automobile in various ways. Most of these lighting units increase the luminance of a surface light source by using a member such as a light guide panel for enhancing transmission of provided light.
In vehicle lighting, light-emitting diodes (LEDs) for implementing high efficiency lighting are lately being used as light sources. The frequency with which LED packages are being used as a light source in flat panel lighting in vehicles is increasing greatly. However, when an LED package is used as a light source, a large amount of light is inevitably required or the number of light emitting devices of an emission surface inevitably increases in order to achieve surface light emission. When a large number of LED packages are used, problems relating to cost, circuit implementation between devices in a curved or narrow space of a vehicle, and heat dissipation occur, leading to critical disadvantages of high-cost and low-efficiency. In particular, the need for various designs for vehicle lighting in limited space is increasing, and these days the demand for implementing three-dimensional (3D) light, or light having a particular shape, is increasing. There is an AMECA regulation that requires the inside of a lamp should be transparent in a vehicle to be exported. Thus, this regulation is necessarily enforced upon export. Thus, designs for stereoscopic lights that satisfy the regulation are required.